I have an Apple 4s (yes it's really old and that might be part of the problem...) and I just started paying for Premium so I could listen to music while I go biking. It worked once. But now when I try to play my music, there's no sound. I can see the progression bar moving so I know it's actually attempting to play the music. All of my audio settings are correct. My other applications play back sounds. Anyone else having this problem?